This invention relates to equipment for surf skiing on the water surface and more particularly to a pair of propulsion sticks to be used with a pair of surf skis.
It is well known that movement on water by human power may be accomplished by oaring, paddling, poling and rowing. Also known is walking or gliding on the water surface with or without water sticks or poles. In recent years, the most successful of such systems for movement on water surface and for towless aquatic skiing has been use of a pair of shoes integral with floating skis with the user's feet on the skis' surface or inside of the skis and a pair of sticks with or without an impact racket. Such an arrangement is made only for walking or strolling on the water surface with or without the support of sticks kicking backward, i.e. by repulsive force due to its impact on the water surface.
True skiing on the water surface has only been possible by use of water skis towed by a motor boat. However, surf skiing in a forward direction by human power can be accomplished on the water surface by displacing backward a certain amount of water by use of a buoyant member having a predetermined cross-sectional area. The buoyant member is repetitively popped up out of the water after having displaced or pushed a predetermined amount of water. This means that the buoyant member should not only be designed to have an appropriate cross-sectional area but also must be water tight to keep proper buoyancy. The buoyant member should also be designed to have minimum hydrodynamic drag during the phase of withdrawal from the water after each push. The buoyant member should be shaped substantially like a diamond and its cross-sectional area should be greater than the maximum cross-sectional area of each ski's body. In accordance with this invention, each ski body is designed to satisfy the following four characteristics; the first is to maximize the speed of each surface ski, the second is to allow a proper maneuverability, the third is to keep a stability and the last is to increase an ability to reride the surf skis when the user falls off. All of these characteristics are satisfied by this invention in order to provide a greater degree of freedom to the surf skier during surf skiing and to make longer trips on the water possible while lessening skier fatigue.
It is, therefore, an object of the present invention to provide equipment for enabling human propulsion in water sports.
Another object is to provide equipment for towless skiing on the water surface.
A further object of the invention is the provision of propulsion sticks designed to provide significant thrust in the water and which easily rise out of the water after each pushing action by the user.
Still another object is to provide surf skis which are optimized for speed, maneuverability, stability and the ability to ride in deep water.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages are realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
To achieve these and other objects, the present invention provides a pair of propulsion sticks, each stick comprising: a rod; a hand grip located at a first end of the rod; and a water-buoyant member located at a second end of the rod. In accordance with the invention, the equipment for towless skiing includes a pair of skis, each ski comprising an elongated ski-shaped body defining a bottom surface and an upper surface; first and second opposed side surfaces extending between the upper and bottom surfaces; the bottom surface curving upwardly in a forward direction at a forward end of the body to meet the upper surface; the first and second side surfaces each defining a shoulder extending downwardly from the upper surface and along the length of the body; each of the shoulders further defining a lower surface substantially perpendicular to the side surface which extends along the length of the body; and the body defining a cavity for receiving a user's foot and the lower part of the user's leg.
The front section of the body of each ski is constructed to experience low drag loss, and the rear section of each ski body is formed of a shape similar to a human heel. Shin guards are provided at the top and front edge of cavities within each ski body with enough space for permitting easy insertion and withdrawal of the lower part of the user's leg. The stability of each ski is also enhanced by extending stabilizing shoulders or side fins from the upper surface of each ski with decreasing slope in the leading part to prevent the effect of nose diving and with increasing slope in the trailing part to aid the prevention of side rotation. The increased facility for the user reriding the skis is provided by a system of connected safety ropes which are attached at rings located at each nose and heel portion of each ski, and the rods of each propulsion stick can be positioned within holding sockets or clamps attached to the upper surface of each ski to further stabilize the positions of the skis with respect to each other.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory but are not restrictive of the invention.